JP2016106348A - Surface light source substrate, surface light source illumination and manufacturing method of surface light source substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide surface light source illumination, such as organic EL illumination and inorganic EL illumination, good in surface light diffusibility, using a surface light source substrate for fixing a light source element.SOLUTION: A surface light source substrate 100 has a 10-point average roughness (Rz) of at least one surface of a substrate of 1 μm or more and 30 μm or less, and an average linear expansion coefficient at 30-130°C of 0-40 ppm/K. The surface light source substrate includes a resin 1 and glass fibers 2a, 2b, and is formed by bringing a surface light source substrate into contact with a transfer mold having irregularities on the surface thereof so that a shape of the mold is transferred.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin substrate for surface light source illumination.

A glass plate is widely used as a substrate for surface light source illumination such as organic EL illumination and inorganic EL illumination. However, the glass plate has problems such as being easily broken, not being bent, and not suitable for weight reduction.
For conventional surface light source illumination, a surface light source is usually produced on a glass plate, and a light diffusion sheet is separately attached to achieve uniform light diffusivity. Therefore, there is a problem that the cost of the member is increased and the cost is increased due to the yield at the time of bonding. On the other hand, resin films used for diffusion sheets usually have low heat resistance and a high coefficient of linear expansion, making it difficult to produce a light source directly.

JP 2001-055646 A JP 2007-249185 A

  A surface light source substrate for fixing a light source element, having a specific surface roughness and further having a low linear expansion coefficient.

Such an object is achieved by the present inventions (1) to (19) below.
(1) A surface light source substrate, wherein an average roughness (Rz) of at least one surface of at least one surface of the substrate is 1 μm or more and 30 μm or less, and the surface ten point roughness is A surface light source substrate, wherein a transfer mold having irregularities on the surface and a surface light source substrate are brought into contact with each other to transfer the shape.
(2) The substrate for a surface light source according to (1), wherein the transfer mold is a resin plate or a metal plate having irregularities on the surface (3) The average interval (Sm) of the irregularities is 0.1 μm or more and 30 μm or less. The surface light source substrate according to (1) or (2).
(4) The surface light source substrate according to (1), wherein the surface light source substrate includes a resin and glass fiber.
(5) The surface light source substrate according to (4), wherein the resin is a heat and / or photocrosslinking resin.
(6) The surface light source substrate according to (4) or (5), wherein the heat and / or photocrosslinking resin is an epoxy resin or an acrylic resin.
(7) The substrate for a surface light source according to any one of (4) to (6), wherein the epoxy resin includes an aromatic glycidyl type epoxy resin.
(8) The substrate for surface light source according to any one of (4) to (7), wherein the aromatic glycidyl type epoxy resin contains a bisphenol type epoxy resin.
(9) The surface light source substrate according to (4), wherein the glass fiber is a glass cloth.
(10) The substrate for surface light source according to any one of (1) to (9), wherein a difference in refractive index between the glass cloth and the resin exceeds 0.02.
(11) The surface light source substrate according to any one of (1) to (10), wherein an average linear expansion coefficient of the surface light source substrate at 30 ° C. to 130 ° C. is 0 to 40 ppm / K.
(12) The surface light source substrate according to any one of (1) to (11), wherein the surface light source substrate has a thickness of 5 to 1000 μm or less.
(13) The surface light source substrate according to any one of (1) to (12), wherein the surface light source substrate has a total light transmittance of 70% or more.
(14) The surface light source substrate according to any one of (1) to (13), wherein the surface light source substrate has a haze value of 70% or more.
(15) The surface light source substrate according to any one of (1) to (14), wherein a glass transition temperature of the surface light source substrate is 130 ° C. or higher.
(16) The surface light source substrate according to any one of (1) to (15), wherein the surface light source substrate has an elastic modulus at 250 ° C. of 1 GPa or more.
(17) Surface light source illumination using the surface light source substrate according to any one of (1) to (16).
(18) A method for producing a substrate for surface light source, which comprises the following steps.
(1) A step of obtaining a sheet in which a glass fiber is impregnated with an uncured resin material.
(2) In the step of sandwiching the sheet obtained in step (1) with two transfer molds, at least one of which has irregularities on the surface.
(3) A step of clamping the sheet with a transfer mold and curing the sheet.
(19) The method of manufacturing a substrate for a surface light source according to (18), wherein the sheet is long and some of the steps are continuously performed.

  It is possible to provide a substrate for a surface light source substrate for fixing a light source element, having a specific surface roughness, a high total light transmittance, and a low linear expansion coefficient.

The figure which shows embodiment of the board | substrate for surface light sources of this invention Diagram showing flat plate transfer mold Diagram showing roll-shaped transfer mold The figure which shows the preparation method using the surface embossing type | mold with sectional drawing which shows embodiment of the board | substrate for surface light sources

Hereinafter, it explains in detail based on a suitable embodiment of the present invention.
In the surface light source substrate of the present invention, the average roughness (Rz) of at least one surface of at least one surface of the substrate is 1 μm to 30 μm, and the average linear expansion coefficient at 30 ° C. to 130 ° C. is 0 ppm or less. / K or more and 40 ppm / K or less.
The substrate for a surface light source of the present invention has a composite layer including a glass cloth composed of an aggregate of glass fibers and a resin material impregnated in the glass cloth. In the present invention, the unevenness on the surface is formed by bringing a transfer mold having the unevenness on the surface into contact with the surface light source substrate, transferring the shape, and forming.
Hereinafter, embodiments of the present invention will be described in detail.

<Substrate for surface light source>
The substrate for a surface light source of the present invention has a surface texture on which at least one surface of the substrate has irregularities, and the irregularities have an average roughness (Rz) of 10 points on the surface of 1 μm to 30 μm. It is.

  In the present invention, the method of providing irregularities on the surface of the substrate can be obtained by bringing the transfer mold having irregularities on the surface into contact with the substrate for the surface light source, transferring the shape, and forming as described above.

  The production of surface irregularities in the present invention will be described in detail.

<Transfer type>
As shown in FIG. 2 or FIG. 3, the transfer mold for transferring the surface irregularities may have irregularities for transfer on the surface of the transfer mold substrate, and the material is not particularly limited. From the viewpoint of use, a resin sheet or a metal sheet is preferable.
Examples of the method for performing uneven processing on the transfer substrate include surface filler fixing, mat processing (sand blasting), embossing, and the like, and an optimal method can be used in a timely manner.

A method of transferring the embossed shape onto the surface of the mold transfer type substrate subjected to embossing or the like can also be adopted.
One method is to prepare a substrate on an embossed mold, cure the substrate, remove the mold, and transfer the unevenness of the mold.

As another method, a method for preparing a transfer mold by immobilizing particles on the surface of a transfer mold substrate will be described.
The simplest and simplest method for providing irregularities on the transfer-type substrate surface is to immobilize particles on the transfer-type substrate surface. For example, a method in which a filler is dispersed in a solvent, applied to the surface of the transfer mold substrate, dried to fix the filler to the surface of the transfer mold substrate, a filler is applied to the surface of the transfer mold substrate, and then pressed and fixed. And a method of fixing the filler by providing an adhesive layer on the surface of the transfer type substrate.

  In addition, as a method of providing unevenness on the surface of the transfer mold substrate by mat processing, sandblasting that physically forms unevenness by hitting an abrasive such as sand on the film surface, or chemically using acid, alkali, solvent, etc. For example, a method of forming irregularities by exposing the surface.

The shape of the transfer mold is not particularly limited, and may be a flat plate shape or a roll shape.
The roll-shaped transfer mold shown in FIG. 3 is suitable for continuous production because the surface light source substrate can be continuously pressed. Specifically, in the roll-shaped transfer mold, it is preferable that the surface of a resin or metal processed into a roll shape is roughened by mat processing (sand blasting), embossing, or mechanical processing. As one form of a method for transferring unevenness by bonding a transfer type substrate obtained by processing a resin into a roll and a surface light source substrate, a transfer method using an apparatus including a feeding portion, a bonding portion, and a peeling portion is given. It is done. The feeding unit feeds the surface light source substrate in one direction. The surface light source substrate may contain the resin precursor in the entire sheet, or may contain the resin precursor on the sheet surface. The bonding unit bonds the transfer-type substrate to the surface light source substrate. A roll or the like is used for bonding. Then, it is preferable to further provide a peeling part in this method. The peeling unit is disposed on the downstream side in the feeding direction of the surface light source substrate, and peels the transfer-type substrate from the surface light source substrate. At the time of peeling, the surface light source substrate holds a state in which surface irregularities are imparted by the transfer type substrate. Therefore, unevenness can be effectively imparted to the surface of the surface light source substrate. In addition, when the surface light source substrate is a heat and / or photocrosslinkable resin described later, a heat and / or photocuring portion may be further provided between the bonding portion and the peeling portion. Thereby, the unevenness | corrugation of the transcription | transfer type board | substrate bonded by the bonding part can be efficiently transcribe | transferred to the board | substrate for surface light sources.

It is most preferable to transfer the unevenness on the transfer mold after the surface light source substrate is produced as described below, and then to be sandwiched and pressed by a transfer mold subjected to surface unevenness processing. Can be produced.
In the case of performing continuously, it is possible to produce unevenness on the surface of the substrate with good reproducibility by using a transfer mold subjected to surface unevenness processing as a mold, which is suitable for mass production.
It is also possible to produce a resin sheet on a transfer mold that has been subjected to surface unevenness processing.

  In the surface light source substrate of the present invention provided with surface irregularities as described above, the average interval (Sm) of the surface irregularities may be 0.1 μm or more and 30 μm or less. Within this range, unevenness is uniformly present on the surface of the substrate, which is advantageous as a substrate for a surface light source in that unevenness in light diffusibility does not occur.

<Substrate for surface light source>
First, an embodiment of the substrate for surface light source of the present invention will be described.
FIG. 1 is a diagram showing an embodiment of a surface light source substrate 100 of the present invention.
A surface light source substrate 100 shown in FIG. 1 has irregularities with Rz of 1 μm or more and 30 μm or less on one surface of a composite layer surface including resin 1 and glass fiber 2.
FIG. 4 shows a method for producing irregularities on the surface light source substrate 100. The mold 5 having a resin layer 4 on the surface of the glass fiber 2 and the resin 1 and embossed embossing is pressed against the resin layer 4. It is to transfer irregularities.
Hereinafter, each component will be described.

<Glass fiber>
Examples of the glass fiber 2 used in the present invention include not only those obtained by simply bundling glass fibers but also fabrics (aggregates of glass fibers) such as woven fabrics and nonwoven fabrics containing glass fibers.
It is particularly preferable to use a glass cloth.
In FIG. 1, the case where the glass fiber 2 is a glass cloth is illustrated as an example. The glass fiber 2 shown in FIG. 1 is composed of a longitudinal glass yarn (warp) 2a and a transverse glass yarn (weft) 2b, and the longitudinal glass yarn 2a and the transverse glass yarn 2b are substantially orthogonal to each other. . Examples of the woven structure of the glass fiber 2 include a plain weave shown in FIG. 1, a nanako weave, a satin weave, and a twill weave.

Examples of the inorganic glass material constituting the glass fiber include E glass, C glass, A glass, S glass, T glass, D glass, NE glass, quartz, low dielectric constant glass, and high dielectric constant glass. . Among these, E glass, S glass, T glass, and NE glass are preferably used as inorganic glass materials because they have few ionic impurities such as alkali metals and are easily available.
In particular, S glass or T glass having an average linear expansion coefficient of 5 ppm or less at 30 ° C. to 250 ° C. is more preferably used.

  Further, the refractive index of the inorganic glass material is appropriately set according to the refractive index of the resin 1 to be used, but the difference in refractive index between the resin 1 and the glass fiber 2 is at least 0.01 or more and 1 or less. Preferably there is. When this difference in refractive index is less than 0.01, there is a high possibility that a problem that the effect on the light diffusibility is not sufficiently exhibited. On the other hand, a glass material having a refractive index difference of 1 or more is extremely small and lacks selectivity. In addition, the refractive index in this application says the refractive index at the time of measuring at 589 nm unless there is particular notice.

  The average diameter of the glass fibers contained in the glass fiber 2 is preferably about 2 to 15 μm, more preferably about 3 to 12 μm, and still more preferably about 3 to 10 μm. As a result, the surface light source substrate 100 capable of achieving both high mechanical and optical characteristics and surface smoothness can be obtained. In addition, the average diameter of glass fiber is calculated | required as an average value of the diameter of 100 glass fibers measured from the observation image, observing the cross section of the board | substrate 100 for surface light sources with various microscopes.

On the other hand, the average thickness of the glass fiber 2 is preferably about 10 to 200 μm.
More preferably, it is about 120 μm. By making the average thickness of the glass fiber 2 within the above range, the surface light source substrate 100 can be made thin, and sufficient flexibility and translucency can be secured, while suppressing deterioration of mechanical properties. Can do.

  When a bundle (glass yarn) made of a plurality of glass fibers is woven to form a woven fabric, the glass yarn preferably contains about 30 to 300 single fibers of glass fiber, and about 50 to 250. More preferably it is included. As a result, the surface light source substrate 100 capable of achieving both high mechanical and optical characteristics and surface smoothness can be obtained.

  Such a glass fiber 2 is preferably subjected to a fiber opening treatment in advance. By the fiber opening process, the glass yarn is widened and the cross section is formed into a flat shape. In addition, a so-called basket hole formed in the glass fiber 2 is also reduced. As a result, the smoothness of the glass fiber 2 is increased and the smoothness of the surface of the surface light source substrate 100 is also increased. Examples of the opening process include a process of spraying a water jet, a process of spraying an air jet, and a process of performing needle punching.

  Moreover, you may make it provide a coupling agent to the surface of glass fiber as needed. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent, and a silane coupling agent is particularly preferably used. As the silane coupling agent, those containing an epoxy group, a (meth) acryloyl group, a vinyl group, an isocyanate group, an amide group or the like as a functional group are preferably used.

  The content of such a coupling agent is preferably about 0.01 to 5 parts by mass, more preferably about 0.02 to 1 part by mass with respect to 100 parts by mass of the glass cloth. More preferably, it is about 02 to 0.5 parts by mass. If the content rate of a coupling agent exists in the said range, the optical characteristic of the board | substrate 100 for surface light sources can be improved. Thereby, for example, a surface light source substrate 100 suitable as a display element substrate is obtained.

  Moreover, when the glass fiber 2 used for this invention is a woven fabric, in this woven fabric, the 2nd ratio which a glass fiber occupies in the cross section of the horizontal direction glass yarn (2nd glass fiber bundle) 2b per unit width is set to " 1 ”, the ratio (relative value) of the first ratio of the glass fibers in the cross section of the longitudinal glass yarn (first glass fiber bundle) 2a per unit width is 0.81 or more and 1.44 or less, 1 It is preferably 0.04 or more and 1.40 or less, more preferably 1.21 or more and 1.39 or less, and further preferably 1.25 or more and 1.35 or less. Thereby, in the surface light source substrate 100, it is possible to achieve the uniformity between the linear expansion coefficient in the vertical direction and the linear expansion coefficient in the horizontal direction, and further improve the light transmittance of the surface light source substrate 100.

  Further, when the longitudinal glass yarn 2a and the lateral glass yarn 2b are the same glass yarn, that is, when the first ratio and the second ratio are substantially equal, the lateral glass yarn per unit width (first When the number of (2 glass fiber bundles) is “1”, the ratio (relative value) of the number of longitudinal glass yarns (first glass fiber bundles) per unit width is 0.9 or more and 1.2 or less. It is preferably from 0.02 to 1.18, more preferably from 1.10 to 1.18, and even more preferably from 1.12 to 1.16. Thereby, in the surface light source substrate 100, it is possible to achieve the uniformity between the linear expansion coefficient in the vertical direction and the linear expansion coefficient in the horizontal direction, and further improve the light transmittance of the surface light source substrate 100.

  The twist numbers of the longitudinal glass yarn (first glass fiber bundle) 2a and the transverse glass yarn (second glass fiber bundle) 2b are each preferably 0.2 to 2.0 / inch. More preferably, it is 3 to 1.6 / inch. When the number of twists of the glass fiber bundle is within this range, the light transmittance is improved.

<Resin material>
For the resin material used in the present invention, for example, a heat and / or photocrosslinking resin can be suitably used.
Specifically, epoxy resins, oxetane resins, isocyanate resins, acrylate resins, olefin resins, cycloolefin resins, diallyl phthalate resins, polycarbonate resins, diallyl carbonate resins, urethane resins, melamine resins Examples include resins, polyimide resins, aromatic polyamide resins, polystyrene resins, polyphenylene resins, polysulfone resins, polyphenylene oxide resins, silsesquioxane compounds, and the like. Among these, an epoxy resin or an acrylic resin is preferably used for the resin material.

<Epoxy resin>
Examples of the epoxy resin or resin precursor used in the present invention include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, or a hydrogenated product thereof, an epoxy resin having a dicyclopentadiene skeleton, Epoxy resin having triglycidyl isocyanurate skeleton, epoxy resin having cardo skeleton, epoxy resin having polysiloxane structure, alicyclic polyfunctional epoxy resin, alicyclic epoxy resin having hydrogenated biphenyl skeleton, hydrogenated bisphenol A skeleton The alicyclic epoxy resin etc. which have these are mentioned, The 1 type, or 2 or more types of mixture of these epoxy resins or resin precursors can be used.

  Specific examples of such glycidyl type epoxy resins or resin precursors include, for example, novolak type epoxy resins such as phenol novolak type epoxy and cresol novolak type epoxy, bisphenol type epoxy resins such as bisphenol A type epoxy and bisphenol F type epoxy, N, Aromatic glycidylamine type epoxy resins such as N-diglycidylaniline, N, N-diglycidyltoluidine, diaminodiphenylmethane type glycidylamine, aminophenol type glycidylamine, hydroquinone type epoxy, biphenyl type epoxy, stilbene type epoxy, triphenol Methane-type epoxy, triphenolpropane-type epoxy, alkyl-modified triphenolmethane-type epoxy, triazine nucleus-containing epoxy, dicyclopentadiene-modified epoxy Epoxy resins such as knol type epoxy, naphthol type epoxy, naphthalene type epoxy, phenol aralkyl type epoxy having phenylene and / or biphenylene skeleton, aralkyl type epoxy such as naphthol aralkyl type epoxy having phenylene and / or biphenylene skeleton, and fluorene skeleton Examples thereof include monofunctional epoxy resins such as glycidyl type epoxy resin, n-butyl glycidyl ether, versatic acid glycidyl ester, styrene oxide, ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, and butyl phenyl glycidyl ether.

Specific examples of the alicyclic epoxy resin or resin precursor include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3, 4-epoxy-6-methylcyclohexanecarboxylate, 2- (3,4-epoxy) cyclohexyl-5,5-spiro- (3,4-epoxy) cyclohexane-m-dioxane, 1,2: 8,9-di Epoxy limonene, dicyclopentadiene dioxide, cyclooctene dioxide, acetal diepoxyside, vinylcyclohexane dioxide, vinylcyclohexylene monooxide 1,2-epoxy-4-vinylcyclohexane, bis (3,4-epoxycyclohexylmethyl) adipate , Screw (3,4 Epoxy-6-methylcyclohexylmethyl) adipate, exo-exobis (2,3-epoxycyclopentyl) ether, 2,2-bis (4- (2,3-epoxypropyl) cyclohexyl) propane, 2,6-bis ( 2, 3
-Epoxypropoxycyclohexyl-p-dioxane), 2,6-bis (2,3-epoxypropoxy) norbornene, diglycidyl ether of linoleic acid dimer, limonene dioxide, 2,2-bis (3,4-epoxy) Cyclohexyl) propane, o- (2,3-epoxy) cyclopentylphenyl-2,3-epoxypropyl ether, 1,2-bis [5- (1,2-epoxy) -4,7-hexahydromethanoindanxyl] Ethane, cyclohexanediol diglycidyl ether and diglycidylhexahydrophthalate, ε-caprolactone oligomers with 3,4-epoxycyclohexylmethanol and 3,4-epoxycyclohexylcarboxylic acid ester-bonded at both ends, epoxidized hexahydro Benji Alcohol and the like.
Moreover, as a bifunctional alicyclic epoxy resin precursor, the alicyclic epoxy structure precursor shown by following Chemical formula (1), (2) or (3) is also mentioned.

[In the above formula (1), -X- is _{-O -, - S -, -} SO -, - SO 2 -, - CH 2 -, - CH (CH 3) -, or -C _{(CH 3) 2} -Represents. ]

    On the other hand, examples of the alicyclic epoxy resin precursor having one epoxycyclohexane ring in the molecule include alicyclic epoxy resins represented by the following chemical formulas (4) and (5).

The resin or resin precursor is polymerized to complete the reaction.

The resin material may be a mixture of two or more of the resins and resin precursors exemplified above.
Moreover, you may use a silsesquioxane type | system | group compound for a resin material with an alicyclic epoxy resin. Examples of such a silsesquioxane compound having an oxetanyl group include OX-SQ, OX-SQ-H, OX-SQ-F (all manufactured by Toagosei Co., Ltd.) and the like.

<Acrylic resin>
On the other hand, as the alicyclic acrylic resin, for example, tricyclodecanyl diacrylate, its hydrogenated product, dicyclopentanyl diacrylate, isobornyl diacrylate, hydrogenated bisphenol A diacrylate, cyclohexane-1,4- Examples include dimethanol diacrylate, and specifically, Hitachi Chemical's Optretz series, Daicel Cytec's acrylate monomer, and the like.

  Furthermore, the resin material used in the present invention preferably has a glass transition temperature of 130 or higher and 150 ° C. or higher, more preferably 170 ° C. or higher, and even more preferably 180 ° C. or higher. Thereby, even if various heat treatments are performed when the surface light source substrate 100 is manufactured and then processed into the surface light source illumination, the surface light source substrate 100 can be prevented from being warped or deformed. it can.

The resin material preferably has a heat distortion temperature of 200 ° C. or higher, and preferably has a coefficient of thermal expansion of 100 ppm / K or lower.
The refractive index of the resin material is preferably as close as possible to the average refractive index of the glass cloth 2 and is preferably substantially the same refractive index. Specifically, the refractive index difference between the two is preferably 0.01 or more and 1 or less, and more preferably 0.02 or more and 1 or less. Thereby, the highly light-diffusing surface light source substrate 100 is obtained.

<Filler>
The surface light source substrate 100 may contain a filler in addition to the above in the resin material. As a result, the haze value can be further increased, or irregularities can be formed on the surface, and a further excellent surface light source substrate can be obtained.
When using a filler, the difference in refractive index between the filler and the resin is preferably 0.01 or more and 3 or less. When this difference in refractive index is less than 0.01, there is a high possibility that a problem that the effect on the light diffusibility is not sufficiently exhibited. On the other hand, there are very few materials having a difference in refractive index of 3 or more and lack selectivity.

  Examples of the material used for the filler include inorganic materials and mixtures thereof. Examples include zinc oxide, zirconium oxide, aluminum oxide, calcium oxide, titanium oxide, silica, or a mixture thereof. Organic materials using acrylic, styrene, or a mixture thereof, etc. Is mentioned. Examples of the shape of the filler include a spherical shape, a rod shape, a planar shape, and a fibrous shape.

The content of the filler is preferably about 1 to 90 parts by mass, more preferably about 3 to 70 parts by mass with respect to 100 parts by mass of the glass cloth.
In addition, when a filler is particle | grains, it is preferable that the conversion particle diameter is 0.1 to 100 micrometer. When the thickness is 0.1 μm or less and 100 μm or more, there is a problem that the diffusion function cannot be sufficiently exhibited. When the filler is fibrous, the fiber diameter is preferably 0.1 μm or more and 100 μm or less. When the thickness is 0.1 μm or less and 100 μm or more, there is a problem that the diffusion function cannot be sufficiently exhibited.

  In the present embodiment, the composite of the glass fiber and the resin material has been described. However, the present invention is not necessarily limited thereto, and it is timely as long as the haze value, the total light transmittance, the linear expansion coefficient, and the like satisfy the physical properties described above. It can be used. Examples of other material systems include the resins listed in the above embodiment, or those obtained by adding additives such as inorganic fillers to these resins.

<Characteristics of substrate for surface light source>
The average thickness of the surface light source substrate 100 as described above is not particularly limited, but is preferably about 5 to 1000 μm, more preferably about 10 to 500 μm and about 15 to 200 μm. When the thickness is not less than the upper limit value, sufficient light transmission cannot be obtained, and when the thickness is not more than the lower limit value, the substrate does not function sufficiently.

  First, the haze value of the surface light source substrate 100 is preferably 70% or more, more preferably 80%, and even more preferably 90%. When the haze value is equal to or higher than the lower limit, the diffusion function can be more sufficiently exhibited.

  Next, the total light transmittance of the surface light source substrate 100 is preferably 70% or more, more preferably 80%, and still more preferably 90%. If the total light transmittance is less than the lower limit, the amount of light in the surface light source illumination using the surface light source substrate 100 may not be sufficient.

  Furthermore, the surface light source substrate 100 preferably has an average linear expansion coefficient at 30 ° C. to 130 ° C. of 0 to 40 ppm / K, more preferably 0 to 30 ppm / K, and still more preferably 0 to 20 ppm / K or less. Since the surface light source substrate 100 having such an average linear expansion coefficient has a sufficiently small dimensional change due to a temperature change, it is possible to reduce distortion applied to the element formed on the substrate, and various problems such as warpage and disconnection of the electrodes. The problem is less likely to occur.

  Moreover, it is preferable that the glass transition temperature of the substrate 100 for surface light sources is 130 degreeC or more and 150 degreeC or more, 170 degreeC or more, More preferably, it is 180 degreeC or more. Thereby, even if various heat treatments are performed when the surface light source substrate 100 is manufactured and then processed into the surface light source illumination, the surface light source substrate 100 can be prevented from being warped or deformed. it can.

  Next, as a characteristic of the surface light source substrate 100, the elastic modulus at 250 ° C. is preferably 1 GPa or more. If it is less than 1 GPa, the shape of the substrate cannot be sufficiently maintained, and element formation may not be sufficiently performed.

<Method for manufacturing substrate for surface light source>
As described above, the surface light source substrate 100 is formed by impregnating the glass fiber 2 with an uncured resin material, and forming (shaping) the resin into a plate shape in this state, and then curing the resin material.

  Specifically, the surface light source substrate 100 is manufactured through a step of obtaining a composite layer 4 by impregnating a glass fiber with a resin varnish and then curing (molding) the resin varnish. Hereinafter, the manufacturing process will be described in detail.

[1] First, a surface treatment is performed by applying a coupling agent to the glass fiber 2. The application of the coupling agent is performed, for example, by a method of immersing the glass fiber 2 in a liquid containing the coupling agent, a method of applying the liquid to the glass fiber 2, a method of spraying the liquid on the glass fiber 2, or the like. . This step may be performed as necessary, and may be omitted.

  [2] Next, a resin varnish is prepared. The resin varnish contains the above-mentioned uncured resin material, other components such as a filler, an organic solvent, and the like, and also contains a curing agent, an antioxidant, a flame retardant, an ultraviolet absorber, and the like as necessary.

(Curing agent)
Examples of such curing agents include cationic curing agents, anionic curing agents, acid anhydrides, crosslinking agents such as aliphatic amines, radical curing agents, and the like, and one or a mixture of two or more of these curing agents. Is used.

  The cationic curing agent releases a substance that initiates cationic polymerization by heating, for example, an onium salt cationic curing agent, an aluminum chelate cationic curing agent, or a substance that initiates cationic polymerization by active energy rays. For example, an onium salt cationic curing agent or a mixture thereof.

The photocationic curing agent may be any one that can react a polyfunctional cation polymerizable compound and a monofunctional cation polymerizable compound by photocationic polymerization. For example, Lewis acid diazonium salt, Lewis acid iodonium salt, Lewis acid Examples include onium salts such as sulfonium salts of acids. Specific examples of the photocationic curing agent include phenyldiazonium salt of boron tetrafluoride, diphenyliodonium salt of phosphorus hexafluoride, diphenyliodonium salt of antimony hexafluoride, tri-4-methylphenylsulfonium of arsenic hexafluoride Salts, tri-4-methylphenylsulfonium salts of antimony tetrafluoride, and mixtures thereof.
Further, depending on the type of the resin material (resin monomer), a photo radical curing agent such as Irgacure series (manufactured by Ciba Japan Co., Ltd.) or the like is also used.

On the other hand, examples of the thermal cationic curing agent include aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, boron trifluoride amine complexes, and mixtures thereof.
Moreover, you may mix the said photocationic hardening | curing agent and a thermal cationic hardening | curing agent.

Although content of such a cationic hardening | curing agent is not specifically limited, It is preferable that it is about 0.1-5 mass parts with respect to 100 mass parts of resin materials, and 0.5-3 weight part is especially preferable.
If the content is less than the lower limit, the curability of the resin material may be reduced, and if the content exceeds the upper limit, the surface light source substrate 100 may become brittle.
In the case of photocuring, in order to accelerate the curing reaction of the resin material, a sensitizer, an acid proliferating agent, and the like can be used together as necessary.

Examples of the anionic catalyst include amine-based curing agents. The molecular weight and structure are not particularly limited as long as the molecule contains two or more primary amines or secondary amines capable of forming a covalent bond with the epoxy group in the epoxy resin. Examples of such amine curing agents include diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine aliphatic polyamine, isophoronediamine, 1,3. -Alicyclic polyamines such as bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornenediamine, 1,2-diaminocyclohexane, N-aminoethylpiperazine, 1,4-bis (2-amino-2-methyl) Propyl) piperazine and other piperazine type polyamines, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, trimethylenebis (4-aminobenzoate), poly Tiger methylene oxide - aromatic polyamines such as di -P- aminobenzoate and the like. These curing agents may be used alone or in combination of two or more curing agents. In addition, use of an imidazole compound alone or in combination with an amine curing agent may also be mentioned. Examples of the imidazole compound include 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4. 2,4-diamino-6- {2-methylimidazole- (1) to which a general imidazole such as 1,5-dihydroxymethylimidazole, 2-C11H23-imidazole, etc., triazine or isocyanuric acid is added to give storage stability } -Ethyl-S-triazine and its isocyanate adduct, etc., can be used, and these can be used alone or in combination.

Examples of acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, maleic anhydride, succinic anhydride, dodecynyl succinic anhydride, dichlorosuccinic anhydride, methyl nadic anhydride, Mellitic acid, methylhexahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, alkylstyrene-maleic anhydride copolymer, Examples thereof include tetrabromophthalic anhydride, polyazeline acid anhydride, chlorendic acid anhydride, benzophenone tetracarboxylic anhydride and the like, and these may be used alone or in combination. In addition, the use of an imidazole compound in combination with an acid anhydride curing agent may also be mentioned. Examples of the imidazole compound include those described above.

(Antioxidant)
As the antioxidant, for example, a phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, and the like are used, and a hindered phenol-based antioxidant is particularly preferably used.
Examples of the hindered phenol antioxidant include BHT and 2,2′-methylenebis (4-methyl-6-tert-butylphenol).

The content of the antioxidant in the resin varnish is preferably 0.01% by mass to 5% by mass, and more preferably about 0.1% by mass to 3% by mass. By making the content of the antioxidant within the above range, a substrate 100 for a surface light source with low optical anisotropy is obtained, and for a surface light source with a small degree of deterioration of optical anisotropy in a reliability test. A substrate 100 is obtained.

  Moreover, it is preferable that the weight average molecular weight of antioxidant is 200-2000, It is more preferable that it is 500-1500, It is further more preferable that it is 1000-1400. If the weight average molecular weight of the antioxidant is within the above range, volatilization of the antioxidant is suppressed and compatibility with a resin material (for example, an alicyclic epoxy resin) is secured. Even when such an antioxidant is subjected to a reliability test such as a wet heat treatment, the surface light source substrate 100 that can remain in the surface light source substrate 100 and suppress deterioration of optical anisotropy is realized. Can do.

Examples of phenolic antioxidants other than hindered phenolic antioxidants include, for example, semi-hindered phenolic antioxidants in which one of the substituents located so as to sandwich the hydroxyl group is substituted with a methyl group or the like. And a hindered phenolic antioxidant in which both of two substituents sandwiching a hydroxyl group are substituted with a methyl group or the like. These are added to the resin varnish in an amount less than that of the hindered phenol antioxidant.
Examples of phosphorus antioxidants include tridecyl phosphite and diphenyl decyl phosphite.

  In addition, the synergistic effect is exhibited by using together a hindered phenolic antioxidant and phosphorus antioxidant. Thereby, the prevention of the oxidation of the resin material (for example, the alicyclic epoxy resin) and the suppression of the deterioration of the optical anisotropy of the surface light source substrate 100 become more remarkable. This is because the hindered phenolic antioxidant and the phosphorus antioxidant differ in the antioxidant mechanism of the resin material, so that they work independently and have a synergistic effect. it is conceivable that.

  The addition amount of antioxidants (particularly phosphorus antioxidants) other than such hindered phenolic antioxidants is preferably about 30 to 300 parts by mass with respect to 100 parts by mass of hindered phenolic antioxidants. And more preferably about 50 to 200 parts by mass. Thereby, a hindered phenolic antioxidant and other antioxidants can exhibit each effect without burying (cancelling), and can bring about a synergistic effect.

The resin varnish may contain an oligomer, a monomer, or the like of a thermoplastic resin or a thermosetting resin as necessary as long as the characteristics are not impaired. In addition, when using these oligomers and monomers, the composition ratio of each component of the resin varnish is appropriately set so that the refractive index of the cured resin composition 3 is substantially equal to the refractive index of the glass cloth 2. .
The resin varnish is obtained by mixing the above components.

[3] Thereafter, the obtained resin varnish is impregnated into the glass cloth 2. When the glass cloth 2 is impregnated with the resin varnish, for example, a method of immersing the glass cloth 2 in the resin varnish, a method of applying the resin varnish to the glass cloth 2 or the like is used. Further, after impregnating the resin varnish into the glass cloth 2, the resin varnish may be further applied from above the resin varnish in an uncured state or after the resin varnish is cured.
Thereafter, if necessary, the resin varnish is subjected to defoaming treatment. Furthermore, the resin varnish is dried as necessary.

[4] Next, the glass fiber 2 impregnated with the resin varnish is heated while being formed into a plate shape. Thereby, the resin material is cured and the composite layer 4 is obtained.
As heating conditions, the heating temperature is preferably about 50 to 300 ° C. and the heating time is about 0.5 to 10 hours, more preferably the heating temperature is about 170 to 270 ° C. and the heating time is about 1 to 5 hours. Is done.

  Moreover, you may make it change heating temperature on the way. For example, initially (initial), the resin varnish may be heated at about 50 to 100 ° C. for about 0.5 to 3 hours, and then heated at about 200 to 300 ° C. for about 0.5 to 3 hours. .

  Moreover, a polyester film, a polyimide film, etc. are used for shaping | molding of a resin varnish, for example. And the surface of a resin varnish can be smooth | blunted and planarized by pressing a film from both sides so that the glass cloth 2 impregnated with the resin varnish may be pinched | interposed.

In addition, when a resin varnish has photocurability, a resin material (resin varnish) is hardened by irradiating the ultraviolet-ray etc. with a wavelength of about 200-400 nm.
Light energy applied (integrated quantity of light) is preferably at 5 mJ / cm ² or more 3000 mJ / cm ² or less, more preferably 10 mJ / cm ² or more 2000 mJ / cm ² or less. If the integrated light quantity is within the above range, the resin material can be cured uniformly and reliably without unevenness.
After curing, the sandwiched film can be peeled off to obtain a resin film.

Moreover, when the sheet | seat which impregnated the uncured resin material to the said glass fiber 2 is long shape, it is possible to implement each process continuously. In this case, some of the steps may be performed continuously. By doing so, continuous production of the resin film becomes possible.
As mentioned above, although the manufacturing method of the board | substrate for surface light sources which concerns on this invention was described, it is not necessarily restricted to this, It manufactures using the method optimal in a timely manner with the material etc. to combine.

  In addition, by using the surface light source substrate described above, surface light source illumination with good light diffusibility can be produced. As a method for manufacturing the surface light source illumination, it is manufactured by a known method. In particular, when a resin film is used as in the present invention, it is preferable to stack a gas barrier layer in order to reduce water vapor / oxygen permeability. Examples of the gas barrier layer include known materials such as inorganic and organic coatings, or hybrid coatings of both. Also, the gas barrier layer is formed by a known method (see above, for example, Japanese Unexamined Patent Application Publication No. 2013-048261 as a manufacturing method of the surface light source illumination).

The method for forming irregularities on the surface of the surface light source substrate is as described above.

  Next, specific examples of the present invention will be described.

<Measurement of average linear expansion coefficient (CTE)>
Using a TMA / SS120C type thermal stress strain measuring device manufactured by Seiko Instruments Inc., the temperature is raised from 30 ° C. to 230 ° C. at a rate of 5 ° C. per minute in a nitrogen atmosphere and held for 20 minutes, and then 5 ° C. per minute. The average linear expansion coefficient of 130 ° C. to 30 ° C. was obtained when it was cooled to 230 ° C. to 30 ° C. The measurement was performed in a tensile mode with a load of 5 g.

<10 average surface roughness (Rz), average spacing of irregularities (Sm)>
From the image obtained by observing the surface of the substrate with a 50 × objective lens with a laser microscope (KEYENCE VK9710), 10 points of 50 μm long line roughness were measured, the average roughness (Rz) of the surface 10 points, and unevenness The average interval (Sm) was calculated according to JIS B0601: 1994, and the average value at 10 locations was obtained.

<Measurement of total light transmittance and haze value>
Based on JIS-K-7361, the total light transmittance of the material was measured using a haze meter NDH: 2000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

Example 1
Epoxy resin, jER828 (refractive index: 1.573, Mitsubishi Chemical), 3 phr of antioxidant (IRGANOX1010 BASF Japan) and 1 phr of photocuring catalyst (SP-170 ADEKA) were added, and the varnish was stirred well. Produced. This varnish was impregnated with E glass cloth # 1081 (refractive index: 1.558, manufactured by Unitika glass fiber) at 70 ° C., and then vacuum degassing was performed at room temperature.

  Vacuum degassed impregnated E glass cloth, transfer material PET on one side, PP film of 25 μm on the other side (Trefan # 25-YM17S: manufactured by Toray, mat film surface roughness Rz: 22.3 μm, Sm: 8.3 μm) And laminated with a laminator heated to 60 ° C., and then cured with UV light.

UV conditions: high-pressure mercury lamp, integrated light intensity of about 800 mJ / cm ²
Thereafter, the transfer material PET was peeled off and removed. The substrate after UV curing was annealed under nitrogen at 250 ° C. for 1 h while being pulled under a load in a nitrogen oven to obtain a glass cloth composite substrate.

This was used as a glass cloth composite substrate for light diffusion. At this time, the obtained glass cloth composite substrate had Rz of 6.5 μm, Sm of 4.3 μm, linear expansion coefficient of 14.4 ppm / K measured value), total light transmittance of 85.1%, and haze of 86. The thickness was 5% and the thickness was 51 μm.

(Comparative example)
A varnish was prepared by adding 1 phr of an antioxidant (IRGANOX1010 BUSF Japan) and 1 phr of a photo-curing catalyst (SP-170 ADEKA) to Celoxide 8000 (refractive index: 1.521, Daicel Chemical). . The varnish was impregnated with T glass cloth # 1081 (refractive index: 1.521, manufactured by Nittobo) at 70 ° C., followed by vacuum defoaming at room temperature.
The impregnated E glass cloth that had been degassed in vacuum was sandwiched from both sides with a transfer material PET, laminated with a laminator heated to 60 ° C., and then cured with UV light.

UV conditions: high-pressure mercury lamp, integrated light quantity 400 mJ / cm ²
Thereafter, the transfer material PET was peeled off and removed. The substrate after UV curing was annealed under nitrogen at 250 ° C. for 1 h while being pulled under a load in a nitrogen oven to obtain a glass cloth composite substrate.

At this time, the obtained glass cloth composite substrate had an Rz of 0.017 μm and an Sm of 3.6.
μm, linear expansion coefficient 11.3 ppm / K, total light transmittance 91.5%, haze 1.43%
The thickness was 56.3 μm.

According to the present invention, it becomes possible to produce a substrate for a surface light source, and within the scope of the present invention, it is possible to provide a substrate having a high total light transmittance and a low linear expansion coefficient. The production of the light source illumination can be simplified and the cost can be reduced.

1 Resin 2a Glass fiber, longitudinal glass yarn (warp)
2b Glass fiber, transverse glass yarn (weft)
3 Filler 4 Resin layer 5 Transfer mold (flat plate)
6 Transfer type substrate 7 Convex part 100 Surface light source substrate 101 Transfer type (flat plate)
102 Transfer type (roll)

Claims (19)

A surface light source substrate,
A substrate for a surface light source having an average roughness (Rz) of at least one surface of the substrate of 1 μm or more and 30 μm or less, wherein the surface of the surface has a roughness of 10 points on a transfer mold and a surface light source A substrate for a surface light source, wherein the substrate is brought into contact with the substrate, transferred in shape, and formed. The surface light source substrate according to claim 1, wherein the transfer mold is a resin plate or a metal plate having an uneven surface. The surface light source substrate according to claim 1, wherein an average interval (Sm) of the unevenness is 0.1 μm or more and 30 μm or less. The surface light source substrate according to claim 1, wherein the surface light source substrate contains a resin and glass fiber. The surface light source substrate according to claim 4, wherein the resin is a heat and / or photocrosslinking resin. The surface light source substrate according to claim 4, wherein the heat and / or photocrosslinking resin is an epoxy resin or an acrylic resin. The surface light source substrate according to any one of claims 4 to 6, wherein the epoxy resin contains an aromatic glycidyl type epoxy resin. The substrate for a surface light source according to any one of claims 4 to 7, wherein the aromatic glycidyl type epoxy resin contains a bisphenol type epoxy resin. The surface light source substrate according to claim 4, wherein the glass fiber is a glass cloth. The surface light source substrate according to any one of claims 1 to 9, wherein a difference in refractive index between the glass cloth and the resin exceeds 0.02. The surface light source substrate according to any one of claims 1 to 10, wherein an average linear expansion coefficient of the surface light source substrate at 30 ° C to 130 ° C is 0 to 40 ppm / K. The surface light source substrate according to claim 1, wherein the surface light source substrate has a thickness of 5 to 1000 μm or less. The surface light source substrate according to claim 1, wherein the surface light source substrate has a total light transmittance of 70% or more. The surface light source substrate according to claim 1, wherein the surface light source substrate has a haze value of 70% or more. The surface light source substrate according to claim 1, wherein a glass transition temperature of the surface light source substrate is 130 ° C. or higher. The substrate for a surface light source according to any one of claims 1 to 15, wherein an elastic modulus at 250 ° C of the substrate for a surface light source is 1 GPa or more. A surface light source illumination using the surface light source substrate according to any one of claims 1 to 16. A manufacturing method of a surface light source substrate, comprising the following steps. (1) A step of obtaining a sheet in which a glass fiber is impregnated with an uncured resin material.
(2) In the step of sandwiching the sheet obtained in step (1) with two transfer molds, at least one of which has irregularities on the surface.
(3) A step of clamping the sheet with a transfer mold and curing the sheet. The method of manufacturing a substrate for a surface light source according to claim 18, wherein the sheet is long and some of the steps are continuously performed.